<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category  Zend
 * @package   Zend_Uri
 * @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd     New BSD License
 * @version   $Id: Uri.php 18951 2009-11-12 16:26:19Z alexander $
 */

/**
 * Abstract class for all Zend_Uri handlers
 *
 * @category  Zend
 * @package   Zend_Uri
 * @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Uri
{
	/**
	 * Scheme of this URI (http, ftp, etc.)
	 *
	 * @var string
	 */
	protected $_scheme = '';

	/**
	 * Global configuration array
	 *
	 * @var array
	 */
	static protected $_config = array(
        'allow_unwise' => false
	);

	/**
	 * Return a string representation of this URI.
	 *
	 * @see    getUri()
	 * @return string
	 */
	public function __toString()
	{
		return $this->getUri();
	}

	/**
	 * Convenience function, checks that a $uri string is well-formed
	 * by validating it but not returning an object.  Returns TRUE if
	 * $uri is a well-formed URI, or FALSE otherwise.
	 *
	 * @param  string $uri The URI to check
	 * @return boolean
	 */
	public static function check($uri)
	{
		try {
			$uri = self::factory($uri);
		} catch (Exception $e) {
			return false;
		}

		return $uri->valid();
	}

	/**
	 * Create a new Zend_Uri object for a URI.  If building a new URI, then $uri should contain
	 * only the scheme (http, ftp, etc).  Otherwise, supply $uri with the complete URI.
	 *
	 * @param  string $uri The URI form which a Zend_Uri instance is created
	 * @throws Zend_Uri_Exception When an empty string was supplied for the scheme
	 * @throws Zend_Uri_Exception When an illegal scheme is supplied
	 * @throws Zend_Uri_Exception When the scheme is not supported
	 * @return Zend_Uri
	 * @link   http://www.faqs.org/rfcs/rfc2396.html
	 */
	public static function factory($uri = 'http')
	{
		// Separate the scheme from the scheme-specific parts
		$uri            = explode(':', $uri, 2);
		$scheme         = strtolower($uri[0]);
		$schemeSpecific = isset($uri[1]) === true ? $uri[1] : '';

		if (strlen($scheme) === 0) {
			require_once 'Zend/Uri/Exception.php';
			throw new Zend_Uri_Exception('An empty string was supplied for the scheme');
		}

		// Security check: $scheme is used to load a class file, so only alphanumerics are allowed.
		if (ctype_alnum($scheme) === false) {
			require_once 'Zend/Uri/Exception.php';
			throw new Zend_Uri_Exception('Illegal scheme supplied, only alphanumeric characters are permitted');
		}

		/**
		 * Create a new Zend_Uri object for the $uri. If a subclass of Zend_Uri exists for the
		 * scheme, return an instance of that class. Otherwise, a Zend_Uri_Exception is thrown.
		 */
		switch ($scheme) {
			case 'http':
				// Break intentionally omitted
			case 'https':
				$className = 'Zend_Uri_Http';
				break;

			case 'mailto':
				// TODO
			default:
				require_once 'Zend/Uri/Exception.php';
				throw new Zend_Uri_Exception("Scheme \"$scheme\" is not supported");
				break;
		}

		if (!class_exists($className)) {
			require_once 'Zend/Loader.php';
			Zend_Loader::loadClass($className);
		}
		$schemeHandler = new $className($scheme, $schemeSpecific);

		return $schemeHandler;
	}

	/**
	 * Get the URI's scheme
	 *
	 * @return string|false Scheme or false if no scheme is set.
	 */
	public function getScheme()
	{
		if (empty($this->_scheme) === false) {
			return $this->_scheme;
		} else {
			return false;
		}
	}

	/**
	 * Set global configuration options
	 *
	 * @param array $config
	 */
	static public function setConfig(array $config)
	{
		foreach ($config as $k => $v) {
			self::$_config[$k] = $v;
		}
	}

	/**
	 * Zend_Uri and its subclasses cannot be instantiated directly.
	 * Use Zend_Uri::factory() to return a new Zend_Uri object.
	 *
	 * @param string $scheme         The scheme of the URI
	 * @param string $schemeSpecific The scheme-specific part of the URI
	 */
	abstract protected function __construct($scheme, $schemeSpecific = '');

	/**
	 * Return a string representation of this URI.
	 *
	 * @return string
	 */
	abstract public function getUri();

	/**
	 * Returns TRUE if this URI is valid, or FALSE otherwise.
	 *
	 * @return boolean
	 */
	abstract public function valid();
}
